1. Field of the Invention
This invention relates generally to vibration damping and, in particular, to a vibration damper for pavement working equipment.
2. Description of the Prior Art
Various types of equipment generate vibration which must be isolated or damped for optimum performance. For example, pavement working equipment such as planers, grinders, saws and the like generate and are subjected to relatively severe vibrational forces which, if left undamped, would seriously impair their performance. A typical piece of pavement working equipment includes a tool such as a saw, grinder or the like operably connected to a prime mover adapted for powering the tool and possibly for driving the piece of equipment.
For example, a ROAD SURFACING APPARATUS is shown in the commonly-assigned Arnswald U.S. Pat. Nos. 4,333,685 and 4,333,686. The Arnswald road planers include cutter heads with circular, diamond-tipped saw blades mounted on a sub-frame which, in turn, is pivotally connected to a main frame. A prime mover comprising an internal combustion engine is also mounted on the sub-frame and provides balast for urging the cutter head into contact with a pavement surface. The engine drives the cutter head and the hydraulically-driven wheels of the planer.
The sub-frame of the Arnswald planer is subjected to vibration from both the engine and the cutter head, both of which are mounted thereon. The internal combustion engine produces primarily vibration in a vertical mode due to the reciprocation of its pistons. The cutter head, on the other hand, produces vibration with respect to the vertical, horizontal (along the direction of travel) and axial (transverse to the direction of travel) spatial axes. The vibration of the cutter head substantially reduces its effectiveness and greatly increases wear on the cutter blades.
The use of small metal particles for shock and vibration absorption has heretofore been proposed. For example, the Hovas U.S. Pat. No. 1,294,467 discloses a shock absorber with a cylindrical container filled with small metal balls which interact with disks mounted on a plunger rod reciprocated within the container. The Brown U.S. Pat. No. 2,417,347 discloses a vibration damper including compartments filled with metal particles ranging in size from shot to fine powder, depending upon the frequency of vibration to be absorbed.
However, heretofore there has not been available either a vibration damping device or method for a road planer and the like with the advantages and features of the present invention.